(683h) Directing Stem Cell Differentiation By Engineering Cell-Cell Adhesion Pathways | AIChE

(683h) Directing Stem Cell Differentiation By Engineering Cell-Cell Adhesion Pathways


Alimperti, S. - Presenter, State University of New York at Buffalo
Row, S., University at Buffalo
George, T. A., Baylor College of Medicine
Agarwal, S., Baylor College of Medicine
Andreadis, S., State University of New York at Buffalo

The differentiation fate of a stem cell is controlled by its microenvironment. Although the role of soluble factors (e.g. TGF-β1) in mesenchymal stem cell (MSC) differentiation towards smooth muscle (SMC) lineage has been studied, the role of intracellular adhesion in this process remains elusive. Our previous studies have shown that cell-cell adhesion is necessary to induce MSC differentiation into vascular fate, particularly through the cell surface molecule, OB-cadherin. To further investigate the role of OB-cadherin in MSC proliferation and differentiation potential, we employed a fusion protein of OB-cadherin with the Fc domain (OB-Fc), which allowed us to study cadherin-cadherin interactions in an isolated manner. In particular, OB-Fc is a chimeric homo-dimer consisting of CH2 and CH3 (Constant Heavy-chain) region of FC  and is linked through the region of the antibody to all five extracellular domains of OB cadherin. Initially, IgG-1 which preferentially bound to FC fragment was coated on a hydrophobic plate and afterwards, Bone Marrow Mesenchymal Stem Cells (BM-MSCs) were plated on OB-FC surface. To this end, these cells exhibited increased proliferation (∼5-fold) and suppressed expression of senescence-associated proteins such as p21 over several passages. At the same time, culture on OB-Fc surface enhanced the BM-MSCs differentiation potential towards the SMC lineage as evidenced by the levels of key myogenic markers such as αSMA and CNN1. In particular, engagement of OB-cadherin increased αSMA expression through ROCK pathway and  its downstream effectors such as SRF. On the other hand, knocking down OB-cadherin using shRNA reversed these effects. Finally, tissue constructs prepared from cells that were propagated on OB-Fc exhibited significantly increased vascular contractility and improved mechanical properties. Notably, these results were confirmed in vivo using OB-cadherin knockout mice (OB-/-). In particular, smooth muscle containing organs from OB-/- animals e.g. bladder exhibited diminished vascular reactivity, decreased collagen content and significantly decreased mechanical properties. To this end, our results demonstrate that engineering OB-FC containing substrates that mimic the in vivo microenvironment promotes MSC proliferation and differentiation potential into SMC, thereby suggesting that this may be a novel and potentially clinically applicable strategy for directing stem cell fate.